Deposition chamber cleaning method including stressed cleaning layer

ABSTRACT

A method for cleaning a deposition chamber includes forming a deposited layer over an interior surface of the deposition chamber, wherein the deposited layer has a deposited layer stress and a deposited layer modulus; forming a cleaning layer over the deposited layer, wherein a material comprising the cleaning layer is selected such that the cleaning layer adheres to the deposited layer, and has a cleaning layer stress and a cleaning layer modulus, wherein the cleaning layer stress is higher than the deposited layer stress, and wherein the cleaning layer modulus is higher than the deposited layer modulus; and removing the deposited layer and the cleaning layer from the interior of the deposition chamber.

BACKGROUND

This disclosure relates generally to the field of semiconductormanufacturing processes, and more specifically to cleaning of adeposition chamber used in a semiconductor manufacturing process.

Deposition processes may be used in semiconductor manufacturing to forma uniform layer of a material, such as a metal, a dielectric material,or a semiconducting material, on a substrate. The material may bedeposited on the substrate using a plasma in a deposition chamber, whichmay be a vacuum chamber. Plasma tools used for deposition processes,such as chemical vapor deposition (CVD), sputtering, and so forth, mayemploy inductive coupling or capacitive coupling to strike and maintainthe plasma in the deposition chamber. One advantage of inductivelycoupled plasmas is that they are generated with much smaller biasvoltage on the substrate, reducing the likelihood of damage thereto. Inaddition, inductively coupled plasmas have a higher ion density, therebyproviding higher deposition rates and mean free paths, while operatingat a much lower pressure than capacitively coupled plasmas. Theseadvantages allow in situ sputtering and/or ion directionality duringprocessing.

High density plasma (HDP) CVD processes may be used to provide acombination of chemical reactions and physical sputtering. HDP-CVDprocesses promote the disassociation of the reactant gases by theapplication of radio frequency (RF) energy to the reaction zoneproximate to the substrate surface, thereby creating a plasma of highlyreactive ionic species. The relatively non-reactive ionic constituents,i.e., argon (Ar), are given high momentum (efield) to dislodge depositedfilm material selectively from specific areas along the profile of thefilm based on a sputter yield curve. The high reactivity of the releasedionic species reduces the energy required for a chemical reaction totake place, thus lowering the required temperature for these processes.

The goal in most HDP-CVD processes is to deposit a film of uniformthickness across the surface of a substrate, while also providing goodgap fill between lines and other features formed on the substrate.Deposition uniformity and gap via fill are very sensitive to sourceconfiguration, gas flow changes, source RF generator power, bias RFgenerator power, gas nozzle design, including symmetry in distributionof nozzles, the number of nozzles, the height of the nozzles above thesubstrate support, and the lateral position of the nozzles relative tothe substrate support. These variables change and processes areperformed within the tool change and as process gases change.

One problem encountered in semiconductor manufacturing is deposition ofmaterial on the deposition chamber itself during deposition on thesubstrate. During deposition, the material deposits not only on thesubstrate, but throughout the chamber interior, on the substrate supportmember (pedestal), and on the gas distribution components (shower head).Over time, built up material on the chamber interior may flake off intothe chamber during subsequent processing of a substrate, resulting inparticle contamination of the substrate, which can compromise theintegrity of the device being fabricated. Thus, the chamber must beperiodically cleaned to prevent particles issues by removing any filmsdeposited on the pedestal, shower head, and chamber wall.

A CVD process may include a chamber clean after every deposition, whilea metal sputtering chamber may be cleaned only after certain cycles.Standard deposition chamber cleaning processes may require multipleiterations of radiofrequency (RF) and remote plasma source (RPS)cleaning steps to thoroughly remove deposited material from the chamberinterior. RF cleaning energizes gas plasma including ions, electrons,radicals, and metastables to remove the carbon or hydrocarbons in thefilm located on the chamber interior through a chemical reaction with anactive gas, such as oxygen. RPS cleaning provides a gentler cleaningstep to further clean around chamber areas including the showerhead.Many iterations of RF and RPS cleaning steps may be necessary in orderto sufficiently clean the chamber, which may require a relatively longperiod of time for the cleaning process. During the cleaning process,the deposition chamber may not be used for device fabrication, whichdecreases throughput for the fabrication process.

After cleaning, the shower head and chamber wall may be coated withanother film prior to subsequent deposition. This additional coatingstep, known as seasoning, is needed to prevent plasma damage to thechamber wall during subsequent deposition processes. The chamber cleanprocess needs to effectively remove all residual films from the chamberbefore seasoning. In order to sufficiently clean all exposed chambersurfaces, the length of time allotted for the cleaning process may beincreased, which increases idle time for the chamber and decreasesthroughput for the manufacturing process. The cleaning process may alsobe performed using higher temperatures, which may effectively overcleanthe chamber surfaces, and increase the cost of consumables and/ormaintenance intervals for the tool. Switching chamber temperature forcleaning is usually not preferred by manufacturing since it requiresadditional time for chambers to stabilize after cleaning Also, excessivecleaning time and temperatures may be damaging to the depositionchamber.

SUMMARY

An exemplary embodiment of a method for cleaning a deposition chamberincludes forming a deposited layer over an interior surface of thedeposition chamber, wherein the deposited layer has a deposited layerstress and a deposited layer modulus; forming a cleaning layer over thedeposited layer, wherein a material comprising the cleaning layer isselected such that the cleaning layer adheres to the deposited layer,and has a cleaning layer stress and a cleaning layer modulus, whereinthe cleaning layer stress is higher than the deposited layer stress, andwherein the cleaning layer modulus is higher than the deposited layermodulus; and removing the deposited layer and the cleaning layer fromthe interior of the deposition chamber.

An exemplary embodiment of a deposition chamber includes a depositedlayer formed over an interior surface of the deposition chamber, whereinthe deposited layer has a deposited layer stress and a deposited layermodulus; and a cleaning layer formed over the deposited layer, wherein amaterial comprising the cleaning layer is selected such that thecleaning layer adheres to the deposited layer, and has a cleaning layerstress and a cleaning layer modulus, wherein the cleaning layer stressis higher than the deposited layer stress, and wherein the cleaninglayer modulus is higher than the deposited layer modulus.

Additional features are realized through the techniques of the presentexemplary embodiment. Other embodiments are described in detail hereinand are considered a part of what is claimed. For a better understandingof the features of the exemplary embodiment, refer to the descriptionand to the drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Referring now to the drawings wherein like elements are numbered alikein the several FIGURES:

FIG. 1 illustrates an embodiment of a method for deposition chambercleaning including a stressed cleaning layer.

FIG. 2 illustrates an embodiment of a deposition chamber after formationof a deposited layer on an interior of the deposition chamber.

FIG. 3 illustrates an embodiment of a deposition chamber of FIG. 2 afterformation of a stressed cleaning layer over the deposited layer.

FIG. 4 illustrates an embodiment of a deposition chamber of FIG. 3 afterRF and RPS cleaning.

DETAILED DESCRIPTION

Embodiments of a method for deposition chamber cleaning includingstressed cleaning layer are provided, with exemplary embodiments beingdiscussed below in detail. The deposition chamber may be a chamber thatis used for any semiconductor deposition process, including but notlimited to chemical vapor deposition (CVD) or sputtering. Afterformation of a deposited layer on a substrate in the chamber, RF and RPScleaning steps are performed in the deposition chamber before use thechamber to form a deposited layer on another substrate. However,successive iterations of RF and RPS cleaning steps may be eliminated bydeposition of a stressed cleaning layer over the deposited layer insidethe deposition chamber before performing RF and RPS cleaning. Thecleaning layer may include a material having a good adhesion to thedeposited layer and a higher stress and modulus as compared to thedeposited layer. The difference in stress between the deposited layerand cleaning layer may cause both the cleaning layer and deposited layerto break off the inside surfaces of the deposition chamber (such as thechamber wall, shower head, or pedestal) with relatively few iterationsof RF and RPS cleaning. Only one iteration of RF and RPS may be requiredto clean the deposition chamber in some embodiments. Reduction of thenumber of RF and RPS cleaning steps allows for increased throughput forthe semiconductor manufacturing process using the deposition chamber,while reducing or eliminating particle issues that may compromise theproperties of a deposited layer formed on a substrate by the depositionchamber.

FIG. 1 illustrates an embodiment of a method 100 for cleaning for adeposition chamber including a stressed cleaning layer. FIG. 1 isdiscussed with respect to FIGS. 2-4. In block 101, a deposited layer isformed on a substrate located on a pedestal located at the bottom of thedeposition chamber. The deposited layer may be formed by CVD orsputtering in some embodiments. The material comprising the depositedlayer may be introduced into the deposition chamber via a shower headlocated at the top of the deposition chamber. The substrate is thenremoved from the deposition chamber. The deposited layer may include anymaterial that may be deposited on a substrate in a semiconductormanufacturing process, including but not limited to a metal, adielectric material, or a semiconductor material. The deposited layermay also form on the interior of the deposition chamber, including thechamber walls, pedestal, and shower head, during formation of thedeposited layer on the substrate, as shown in FIG. 2. FIG. 2 illustratesan embodiment 200 of a deposition chamber 201 after formation of thedeposited layer 204 on a substrate (not shown) and on the interior ofthe deposition chamber 201, and after removal of the substrate from thepedestal 203. Deposited layer 204 forms on the interior walls ofdeposition chamber 201, and also on shower head 202 and pedestal 203.Deposited layer 204 is shown for illustrative purposes only; a depositedlayer may form on any portion of the interior of a deposition chamberwith varied thickness, uniformity, and distribution in various processembodiments. Deposition chamber 201, with shower head 202 and pedestal203, is also shown for illustrative purposes only; method 100 may beimplemented using any appropriate configuration of deposition chamber.In some embodiments, deposited layer 204 may include both a seasoninglayer, which is deposited over the interior of chamber 201 beforeintroduction of the substrate into the chamber and acts to protect theinterior of chamber 201 during deposition on the substrate, and a layerof the material that is subsequently deposited on the substrate. Theseasoning layer may include silicon nitride (SiN) in some embodiments.Deposited layer 204 has a stress and modulus that is determined by thematerial comprising deposited layer 204.

In block 102, a stressed cleaning layer 301 is deposited over depositedlayer 204 in the interior of deposition chamber 201, as shown embodiment300 of FIG. 3. The material comprising cleaning layer 301 may beintroduced into the deposition chamber 201 via shower head 202. Thecleaning layer 301 may be formed by CVD or sputtering in someembodiments. The material comprising cleaning layer 301 is selected suchthat cleaning layer 301 has a good adhesion to the deposited layer, anda stress and modulus that is higher than the stress and modulus ofdeposited layer 204. The cleaning layer can be readily deposited butwith different process parameter settings, such as flowrate, additionalgas/chemicals, or radio frequency power. The difference in stress andmodulus between cleaning layer 301 and deposited layer 204 inducesstress in deposited layer 204. In an embodiment in which deposited layer204 includes an low k dielectric, such as amorphous silicon nitridecarbon hydrogen material (SiN_(x)C_(y)H), having a stress from about−140 to about −180 megapascals (mPa), the cleaning layer 301 may includea dielectric material such as silicon nitride carbide (SiNC) having astress from about −400 to about −490 mPa. The adhesion between the SiNCcleaning layer and the SiN_(x)C_(y)H deposited layer is greater than 5J/m². The modulus in the cleaning layer 301 is about 70 gigapascals(GPa) higher than that in the deposited layer 204. The cleaning layerwith the higher modulus represents a stronger material than thedeposited layer 204, so the cleaning layer 301 provides sufficientmechanical strength. Cleaning layer 301 is shown for illustrativepurposes only; the cleaning layer may form on any portion of the surfaceof deposited layer 204 with varied thickness, uniformity, anddistribution in various embodiments.

In block 103, RF and RPS cleaning are performed in the depositionchamber 201. The stress induced in the deposited layer 204 by cleaninglayer 301 may cause the deposited layer 204 and cleaning layer 301 tobreak off from the surfaces including the interior walls of depositionchamber 201, the shower head 202, and pedestal 203, requiring relativelyfew iterations of RF and RPS cleaning In some embodiments, only a singleiteration of RF and RPS cleaning may be necessary to remove depositedlayer 204 and cleaning layer 301 from the interior of deposition chamber201. FIG. 4 illustrates an embodiment 400 of a deposition chamber 201after RF and RPS cleaning, and removal of deposited layer 204 andcleaning layer 301. After RF and PRS cleaning are completed, thedeposition chamber 201 shown in FIG. 4 may have a seasoning layer (notshown) formed on the interior of the deposition chamber 201 beforeintroduction of a substrate into the chamber 201 for processing. Theseasoning layer may include SiN in some embodiments, and may act toprotect the interior of deposition chamber 201 from plasma damage duringsubsequent deposition of material on a substrate.

Reduction in the number of RF and RPS cleaning steps may significantlyincrease throughput for the deposition chamber. In one embodiment of aCVD manufacturing tool, throughput may increase by about 25% due to thereduction in cleaning time.

The technical effects and benefits of exemplary embodiments includeshorter cleaning time and higher throughput for a deposition chamberused for deposition in a semiconductor manufacturing process.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an”, and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

The invention claimed is:
 1. A method for cleaning a deposition chamber,the method comprising: forming a deposited layer consisting of adeposited layer material on a substrate of a semiconductor manufacturingprocess and over an interior surface of the deposition chamber, whereinthe deposited layer is formed by chemical vapor deposition; removing thesubstrate of the semiconductor manufacturing process from the interiorof the deposition chamber after formation of the deposited layer; afterremoving the substrate from the deposition chamber, forming a cleaninglayer over the deposited layer, wherein no substrate of anysemiconductor manufacturing process is present in the deposition chamberduring formation of the cleaning layer, wherein the cleaning layerconsists of a cleaning layer material comprising silicon nitride carbidethat adheres to the deposited layer, and wherein the cleaning layermaterial is a different material from the deposited layer material; andremoving the deposited layer and the cleaning layer from the interior ofthe deposition chamber.
 2. The method of claim 1, wherein the cleaninglayer is formed by chemical vapor deposition.
 3. The method of claim 1,further comprising: forming a first seasoning layer on the interior ofthe deposition chamber before forming the deposited layer, wherein thesubstrate is not located in the deposition chamber during formation ofthe first seasoning layer; placing the substrate in the depositionchamber after forming the first seasoning layer and before forming thedeposited layer; and removing the first seasoning layer from theinterior of the deposition chamber with the deposited layer and thecleaning layer.
 4. The method of claim 3, wherein the first seasoninglayer comprises silicon nitride.
 5. The method of claim 1, furthercomprising forming a second seasoning layer on the interior of thedeposition chamber after removing the deposited layer and the cleaninglayer from the interior of the deposition chamber.
 6. The method ofclaim 5, wherein the second seasoning layer comprises silicon nitride.7. The method of claim 1, wherein the deposited layer material comprisesa metal.
 8. The method of claim 1, wherein the deposited layer materialcomprises a semiconductor material.
 9. The method of claim 1, whereinthe deposited layer material comprises a dielectric material.
 10. Themethod of claim 1, wherein removing the deposited layer and the cleaninglayer from the interior of the deposition chamber comprises aradiofrequency cleaning step and remote plasma source cleaning step. 11.The method of claim 1, wherein the deposited layer material comprises alow k dielectric material.
 12. The method of claim 11, wherein the low kdielectric material that comprises the deposited layer materialcomprises an amorphous silicon nitride carbon hydrogen (SiN_(x)C_(y)H)material.
 13. The method of claim 1, wherein the adhesion between thedeposited layer and the cleaning layer is greater than 5 joules/meter².14. The method of claim 1, wherein the cleaning layer induces a stressin the deposited layer.
 15. A method for cleaning a deposition chamber,the method comprising: forming a deposited layer consisting of adeposited layer material on a substrate of a semiconductor manufacturingprocess and over an interior surface of the deposition chamber; removingthe substrate of the semiconductor manufacturing process from theinterior of the deposition chamber after formation of the depositedlayer; after removing the substrate from the deposition chamber, forminga cleaning layer over the deposited layer, wherein no substrate of anysemiconductor manufacturing process is present in the deposition chamberduring formation of the cleaning layer, wherein the cleaning layerconsists of a cleaning layer material comprising silicon nitride carbidethat adheres to the deposited layer, wherein the cleaning layer isformed by chemical vapor deposition, and wherein the cleaning layermaterial is a different material from the deposited layer material; andremoving the deposited layer and the cleaning layer from the interior ofthe deposition chamber.